Ground connector for terminal strip



July 12, 1966 w. STAFFEL 3,260,986

GROUND CONNECTOR FOR TERMINAL STRIP Filed July 15, 1965 r Filip/'6 Avid, /mm ply/MW United States Patent 3,260,986 GROUND CONNECTOR FOR TERMINAL STRIP Wilhelm Stafiel, Kouigswinter, Haus Margaretha, Germany Filed July 15, 1963, Ser. No. 294,894 2 Claims. (Cl. 339-198) The present invention relates to a connector for grounding wires and neutral conductors.

The metal parts of switchgear must be grounded, which evidently also applies to the bars carrying the connectors or connecting terminals. Said bars were hitherto drilled through at some point and the ground wire was secured in the perforation so contrived. The neutral conductors frequently included in multi-core cables moreover had to be connected at some point close to the terminal strip, for which purpose a bar or rail was frequently installed in addition for said neutral conductors, close to the terminal strip. Supplementary fittings work can be eliminated in both cases, by utilizing a suitable connector for the ground and neutral conductors, which may conjointly with the connectors made of insulating material and in the same manner as the latter, be aflixed to the bar carrying the connectors at any optional point on the anterior side of said bar.

A connector has already become known for the grounding of terminal strips or the like, which is secured to the terminal strip by means of a clip or the like. Its disadvantages are, that it cannot in the same manner as the connectors made of insulating material simply be inserted from the front while operating a catch mechanism, a contact rail carrying said connector must be pressed against the terminal bar in such manner as to establish contact by means of an opposed clip and of a clamping screw traversing both, and said opposed clip must be engaged under the flanges of the terminal bar after the contact rail has been placed thereon, before the clamping screw may be tightened. This ground connect-or is longer moreover than the standard insulated connectors of said bar, so that it occupies more space and spoils the otherwise uniform ap' pearance of the row of connectors.

The object of the present invention is to eliminate these disadvantages, and is essentially characterized by the facts that a metal connector unit is contrived in the same shape as the base of the iTshlating case of conventional connectors, comprises a catch mechanism and has the same width as said conventional connectors, and that a screw is employed to establish a permanent contact with the bar carrying said connectors.

A metal connector unit of this form does not spoil the appearance of the terminal strip, its terminal post or the like no longer projecting beyond said strip. Said connector fits closely between the insulated connectors. Due to its plane sides, this ground and neutral wire connector is suitable moreover to secure the extremity of a row of snap-in connectors comprising spring members.

The principal features of the invention are that a spring catch device engages under one flange of the terminal bar, and that the screw bears on the other flange of said bar and permanently presses the portion of the connector engaging beneath said flange against the underside of the latter. This form of construction has the advantage that the ground wire or neutral wire connectors may be inserted in the same manner as the insulated connectors to engage like the latter by virtue of the spring member incorporated therein.

In another form of embodiment of the invention, the extremity of the one flange of the carrying bar engages in a recess of the connector when the latter is displaced by the tightening of a screw owing to the tapering extremity of said screw exerting a thrust with one half there- 3,269,986 Patented July 12, 1966 of on the top edge of the other flange, permanent contact pressure thereby being attained at both contact points.

Although the ground or neutral wire connector may also be inserted from the top into any optional point of the bar carrying the connector, the connector must in the case of this form of construction be secured to the terminal bar immediately in such manner as to establish contact by tightening the slotted screw. This offers the advantage that a connection difficult to release corresponding to regulations covering earth Wires is mandatorily establisherd.

It is of importance that the tip of the screw should exhibit sharp edges or the like in order to remove a surface layer of low conductivity which may be present on said bar.

Both forms of embodiment exhibit a draw strap or the like to act as a terminal clamp which is loss-proof and mounted on a projection on the carrying bar.

Said terminal draw strap offers the advantage that even multi-wire conductors have their straight extremity satisfactorily engaged and pressed against the metal projection, the correct depth of insertion being determined by the body of said connector.

A bore or tapped bore in the middle of the top surface of said connector may be used to afiix a name plate, a cover, a socket, a plug or the like.

The present invention is hereinafter to be particularly described by way of example but by no manner of means of limitation, with reference to the accompanying drawings, wherein FIGURE 1 is a side elevational view, partly in section showing a first form of the invention,

FIGURE 2 is a top plan view thereof,

FIGURES 3, 4 and 5 are side elevational views, partly in section, showing an alternative form of the invention in three stages during insertion and screwing tight,

FIGURE 6 is a front elevational view of a terminal strip with an interposed grounding or neutral wire connector according to the invention.

The bar 1 used to carry said connectors is of the same standard section in both cases. The metal connector unit corresponding in shape to the base of the insulating case of conventional connectors is inserted between and contiguous to the insulated connectors 2 and 3. The numeral 4 designates a metallic connector unit in the first form of embodiment in FIGURE 1. It comprises a screw 5 cont-rived to produce permanent contact with the bar 1, at the points 6 and 7 in particular. A projection 8 mounted on the unit 4 in displaceable 'but loss-free manner carries the draw strap 9, into the aperture whereofmarked 10- the straight extremity of the ground or neutral wires is to be inserted, whereupon said extremity is forced against the projection 8 of the connector 4 by tightening the strapclamping screw 11. In the form of embodiment according to FIGURE 1, the metal connector comprises spring-catch device, being the essentially known steel-wire spring catch 12 in extensive use in insulated connectors. The connector thus already seats securely in the bar carrying the connectors after insertion, owing to said catch device. A contact thrust difficult to release is then established by means of the screw 5 bearing at 7 on the top face of the narrow flange portion of the bar 1, and at 6 presses the corresponding face of the connector unit to the underside of said flange. Any surface layer of low conductivity which may be present on the bar at the point 7 is roughened by sharp edges contrived on the tip of the slotted screw 5 in order to improve contact. A bore or tapped bore 13 in the middle of the top side of the connector may be used to secure a name plate, a cover, or a socket for test prongs for example, or for a plug.

In the form of embodiment shown in FIGURES 3 to 5, the numeral 14 designates the metallic connector unit corresponding in shape to the vase of the insulating case of conventional connectors. Said connector also comprises a screw 15 for permanent contact with the bar 1 at the points 16, 17 and 18 in particular. As in the first form of embodiment according to FIGURE 1, a terminal draw strap 9 is analogously disposed on a projection 8 in 'displ-aceable but loss-free manner. The ground or neutral wire connector according to FIGURES 3 to 5 does not comprise a spring catch, the connector uni-t merely exhibiting a shallow recess 19 wherein there engages the wide flange portion of said bar when the screw is tightened after the insertion of the connector. Said screw 15 has a tapering point and initially bears with its tip on the extheme edge of the narrow flange portion of said hat. On being tightened, the conical face at the tip of the screw exerts a thrust on the extreme edge referred to in such manner, that the connector unit as a whole is displaced towards the left, the extreme edge of the wide flange portion of said bar engages in the recess 19 to establish a satisfactory contact with the connector unit at this point. In the second embodiment, the connector unit also exhibits a central bore or tapped bore 13 usable for various purposes.

The present invention is evidently not limited to the forms of embodiment hereinbefore described, and various detail modifications or technically equivalent means may be introduced therein without thereby exceeding the scope of the invention.

What I claim is:

1. A connector assembly comprising,

a channel-shaped metallic mounting bar having two opposed flanges,

an electrical connector having a recess on one side which receives one of said flanges, a spring wire on the opposite side which engages under the other flange of said mounting bar, and

a screw threaded in said connector and bearing against the flange received in said recess to clamp said flange between said screw and said connector.

2. A connector according to claim 1, characterized by the fact, that the tip of said screw exhibits sharp edges in order to remove any surface layer of low conductivity which may be present on said bar.

References Cited by the Examiner UNITED STATES PATENTS 2,290,900 7/1942 Thomas 339-95 X FOREIGN PATENTS 1,038,149 12/ 1959 Germany. 1,071,808 12/ 1959 Germany.

168,938 4/1934 Switzerland. 272,078 11/1950 Switzerland. 891,610 3/ 196 2 Great Britain. 920,357 3/ 1963 Great Britain.

PATRICK A. CLIFFORD, Primary Examiner. ALFRED S. TRASK, Examiner. 

1. A CONNECTOR ASSEMBLY COMPRISING, A CHANNEL-SHAPED METALLIC MOUNTING BAR HAVING TWO OPPOSED FLANGES, AN ELECTRICAL CONNECTOR HAVING A RECESS ON ONE SIDE WHICH RECEIVES ONE OF SAID FLANGES, A SPRING WIRE ON THE OPPOSITE SIDE WHICH ENGAGES UNDER THE OTHER FLANGE OF SAID MOUNTING BAR, AND A SCREW THREADED IN SAID CONNECTOR AND BEARING AGAINST THE FLANGE RECEIVED IN SAID RECESS TO CLAMP SAID FLANGE BETWEEN SAID SCREW AND SAID CONNECTOR. 